In a switching system, a line card chassis (LCC) is generally formed by at least one line card (LC) and at least one switch fabric card (FC). Each LC in an LCC includes at least one fabric interface chip (FIC), and each FC includes at least one switch element (SE). As shown in FIG. 1, in a line card chassis LCC0, there are 16 LCs (LC0 to LC15) and 8 FCs (FC0 to FC7), and there are altogether 32 FICs (FIC0 to FIC31) and 16 SEs (each FC shown in FIG. 1 includes two SEs), where on an FIC side of each SE (that is, a left side of an SE shown in the figure), 64 links (SerDes) are configured to interconnect each SE with all FICs of LCC0, and the other 64 SerDes links (that is, on a right side of an SE shown in FIG. 1) are configured to connect each SE to other LCCs, so that capacity expansion is performed on the switching system.
During capacity expansion, a switching system generally needs to meet a traffic line rate, so that an LCC back-to-back connection or an LCC star connection is generally used during capacity expansion of a switching system in the prior art. The back-to-back connection is shown in FIG. 2, where 64 SerDes links on a right side of an SE of LCC0 are used to connect FCs of LCC0 with FCs of LCC1 in pairs (that is, SEs with a same sequence number on the FCs are also connected in pairs), so that a capacity of a single chassis is doubled; and the star connection may be shown in FIG. 3, where a dedicated fabric card chassis (FFC) is used to connect multiple LCCs together, that is, 4 LCCs in FIG. 3 are connected by using 128 SerDes links provided by FCC0, so as to achieve an objective of capacity expansion.
However, although both the two connection manners in the prior art can meet a traffic line rate of a system, the back-to-back connection manner causes limited capacity expansion, and the star connection manner causes high capacity expansion costs of the system. Therefore, desirable capacity expansion cannot be achieved in both manners.